1. Field of the Invention
The invention relates to a turning mechanism for providing a turning motion, the mechanism comprising at least one power element which is arranged to generate the turning force for the turning motion, and at least one damping element which is arranged to control the speed of the turning motion.
The invention further relates to a hinged electronic device which comprises at least a first part and a second part arranged to turn with respect to the first part.
2. Brief Description of Related Developments
Folding electronic devices are known which comprise a base part and a turning cover part which is attached to the base part and can be turned by means of hinges. The above-mentioned electronic devices are typically e.g. mobile phones, communicators, portable computers, laptops, palmtops or other similar devices. The base part and the cover part of the device can be folded against each other to facilitate carrying and handling of the device, for example. On the other hand, by opening the device into its use position, i.e. by turning the cover part apart from the base part, we obtain a screen the size of which usually equals the size of substantially the whole cover part, and a keyboard the size of which equals the size of substantially the whole base part. Naturally, the device may comprise more than two parts which turn with respect to each other.
To increase the ease of use, the hinge structure of the device can be provided with opening elements which facilitate the opening motion, such as springs which generate the opening force needed to turn the parts into the use position, i.e. when the locking that locks the parts against each other is released, the opening elements force the parts open. To guarantee a reliable opening motion in every situation, the opening members are made rather strong. This results in a rapid opening motion, which often causes a loud and unpleasant sound as the parts hit the limiters of the opening motion. Opening of the device is not particularly pleasant and does not give a good impression of the quality of the device in this respect. In addition, a sudden stop of a strong and rapid movement may stress and even break device components, which naturally causes inconvenience and costs to the user. The stress is particularly high when the cover part is relatively heavy and the opening element strong. Naturally, the structures of the device can be dimensioned to withstand the stress caused by the opening motion better, but in that case the other operating characteristics of the device may suffer, the weight and size of the device will increase and the price rise.
Solutions are also known e.g. from household appliances and automotive engineering which comprise opening members and damping elements for slowing down the opening motion. For example, U.S. Pat. No. 4,614,004 discloses a solution in which a rotor rotating in a cylinder filled with liquid brakes the opening motion of a lid opened by spring force in a cassette recorder or the like. To achieve sufficient damping, a transmission ratio is provided between the lid and the rotor by means of cogwheels. U.S. Pat. No. 4,721,310 discloses an opening mechanism in which springs pull open the lid of a vanity mirror mounted in the visor of a vehicle. The edge of the lid is pressed against a flexible counter surface along which the edge of the lid moves, thus braking the opening motion. These solutions are functional as such but since their structures are relatively complex and large, they are unsuitable for small electronic devices the size of which will still decrease. Particularly if the electronic device comprises more than two hinged parts, the structure will be rather complicated and expensive.
An object of the present invention is to provide a folding electronic device in which the opening or closing mechanism functions in a controlled manner. A further object of the invention is to provide an opening or a closing mechanism which needs a small amount of space and has low production costs. It should be noted that hereinafter in this application the term device is used to refer to hinged electronic devices.
The turning mechanism of the invention is characterized in that the damping element comprises a substantially cylindrical casing, that a spindle is mounted inside the casing using a clearance fit, the spindle being connected to the power element to allow relative rotational movement between the spindle and the casing along with the turning motion, and that the clearance fit between the casing and the spindle is provided with an elastic medium which controls the turning motion of the casing with respect to the spindle and dampens the stopping of the turning motion.
The electronic device according to the invention is characterized in that the device comprises a turning mechanism for turning the first part with respect to the second part, that the turning mechanism comprises a power element which is arranged to generate the turning force for the turning motion, and a damping element which is arranged to control the speed of the turning motion and which substantially comprises a cylindrical casing inside of which a spindle is mounted using a clearance fit, the spindle being connected to the power element so that the spindle rotates with respect to the casing along with the turning motion, and that the clearance fit between the casing and the spindle is provided with an elastic medium which controls the turning motion of the casing with respect to the spindle and dampens the stopping of the turning motion.
The basic idea of the invention is that the turning motion caused by the power element of the turning mechanism is slowed down with a damping element which comprises a casing, a spindle with a clearance fit which is arranged inside the casing and rotates with respect to the bushing along with the motion, and an elastic medium which is placed between the bushing and the spindle and controls the rotation of the spindle with respect to the bushing so that the parts of the device turn with respect to each other suitably slowly and so that this motion stops in a smooth and controlled manner. The idea of a preferred embodiment is that the power element is integrated into the damping element to allow the elastic medium both cause the turning motion and slow down the turning motion and the stop thereof The idea of a second preferred embodiment is that the spindle is substantially round in cross-section and that the elastic medium is elastic adhesive material which sticks onto the casing and/or the spindle, preventing their free rotation with respect to each other. The idea of a third preferred embodiment is that the power element used as the source of the turning force is a spring, preferably a torsion spring, which is arranged substantially parallel with the damping element and preferably so that the torsion spring simultaneously functions as the hinge pin of at least one hinge.
An advantage of the invention is that the turning mechanism is small and thus easy to mount in small devices, too. The structure of the turning mechanism is very simple, and consequently its production and assembly costs are low and its function reliable. The substantially round spindle is very simple to produce, and the elastic medium consisting of acrylic adhesive can be installed in the damping element without difficulty; furthermore, its damping property remains substantially the same from one turn to another. Thanks to its shape, the torsion spring is easy to mount in the device so that it takes as little space as possible. The hinge pin integrated into the torsion spring decreases the number of components in the device and thus also the costs resulting from the components.